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Magnets in iPhone® Series 12 Can Interfere with Some Implanted Cardiac Devices


American Heart Association   (AHA)

June 2, 2021

Journal of the American Heart Association Report

Research Highlights:

  • For some cardiac patients, a pacemaker or implantable cardioverter defibrillator is needed to help keep the heart beating normally.
  • People who have an implanted cardiac device should not be near electronic devices that have magnets or produce electromagnetic waves because they can interfere with the cardiac device’s functions.
  • Magnets in the iPhone 12® series, which allow the phones to be charged wirelessly, are stronger than the magnets found in earlier generations of iPhones.
  • In a small study of different types of pacemakers and implantable cardioverter defibrillators, 11 of 14 cardiac devices experienced interference when an iPhone 12 Max Pro was held close to the cardiac device (within 1.5 cm), even when the device was still in the manufacturer’s sealed package.

People who have a pacemaker or an implantable cardioverter defibrillator should be aware that the magnets used in the wireless charging technology for the series 12 models of the Apple iPhone can affect how the cardiac devices work if the phones are stored or used in close proximity to the implanted cardiac device, according to new research published today in the Journal of the American Heart Association, an open access journal of the American Heart Association..

In a small study, researchers found when the phone was held directly over the skin near the implantable cardiac devices or directly over the still-packaged cardiac device, the magnetic technology in the iPhone 12 Pro Max® caused interference in nearly 80% (11 of 14) of the pacemakers and implantable cardioverter defibrillators evaluated.

An internal pacemaker — a small device that uses electric stimulation to help keep the heart beating regularly — is surgically placed just under the skin and connected to the heart with tiny wires. An implantable cardioverter defibrillator is a device also placed under the skin and attached to the heart so that if an abnormal heart rhythm is detected it can initiate a small electric shock to restore a normal heartbeat. Both types of devices offer therapeutic and lifesaving solutions for people with specific cardiac conditions such as arrhythmia, congenital heart disease or deterioration of the heart muscle due to age. Each year in the United States, more than 50,000 patients, 65 years of age and older, receive implantable cardioverter defibrillators.

While the electromagnetic waves of some portable electronics and machinery can interfere with how implantable cardiac devices operate, modern cell phones have previously been found to pose little risk. On May 13, 2021, the U.S. Food and Drug Administration issued an update regarding magnet technology in portable electronics such as cell phones and smart watches that have magnets: the FDA recommends keeping all electronic devices with magnets at least six inches away from implanted medical devices, such as pacemakers and defibrillators. Apple offers the same guidance regarding its MagSafe products.

Researchers tested 14 different cardiac implantable electronic devices made by three major manufacturers to investigate if the magnetic components of the iPhone 12 Pro Max® would affect how the devices work. Three of the cardiac devices tested were implanted in a patient and were tested through the patient’s skin. The remaining 11 cardiac devices were new and still in the manufacturers’ packaging. Each device was first tested using a donut magnet to evaluate if magnet mode — the mode activated by health care professionals to change the device functioning or turn it off — was achievable. For the three implanted devices, the iPhone 12 Pro Max® was placed directly on the skin over the cardiac device to check for activation of magnet mode. For the new cardiac devices still in packages, wireless connection was established with each, and the iPhone 12 Pro Max® was placed within 1.5 cm directly over the cardiac device still in the sealed manufacturer’s package.

Clinically identifiable magnetic interference was detected in all three of the implanted devices, and in about three quarters (eight of the 11) of the new, in-the-package cardiac devices. All interference was triggered by the proximity of the series 12 iPhone; no other magnetic devices were near. In total, 11 of the 14 devices (79%) experienced malfunctioning when within 1.5 cm of the iPhone 12 Pro Max.

“We have always known that magnets can interfere with cardiac implantable electronic devices, however, we were surprised by the strength of the magnets used in the iPhone 12  magnet technology,” said lead study investigator Michael Wu, M.D., assistant professor of medicine, clinician educator and director of the Clinical Cardiac Electrophysiology Fellowship Program in the cardiology division at the Rhode Island and Miriam Hospital’s Lifespan Cardiovascular Institute and Brown University’s Warren Alpert School of Medicine. “In general, a magnet can change a pacemaker’s timing or deactivate a defibrillator’s lifesaving functions, and this research indicate the urgency for everyone to be aware that electronic devices with magnets can interfere with cardiac implantable electronic devices.”

The researchers note there are some limitations, including the small number of devices tested in this study, therefore the results may not be the same for all pacemakers and implantable cardioverter defibrillators.

“The American Heart Association and manufacturers of pacemakers and implantable cardioverter defibrillators have long recommended that cell phones be used in the ear opposite the side of the body of an implanted device, and that the cell phones be kept at least 10 cm away from the device, therefore not in a shirt or coat pocket on the same side as the cardiac device,” said N.A. Mark A. Estes, M.D., professor of medicine and director of the Clinical Cardiac Electrophysiology Fellowship Program at the Heart and Vascular Institute of the University of Pittsburgh School of Medicine, and an American Heart Association volunteer. “While the risk from temporary interference was only tested with specific devices and cell phones, the Association reminds people with cardiac implantable electronic devices to remain informed of the latest FDA guidance for their heart device, the manufacturers’ safety guidelines and to contact their health care professional with any questions or concerns.“


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